A new model system for the study of the animal innate immune response to fungal infections.

摘要

The association of the model organism Caenorhabditis elegans and the fungus Pleurotus ostreatus gives the possibility to study the molecular and genetic mechanisms of the early stages of the spatial and temporal interactions of animals with fungal pathogens. We identified the stages of the infection process of P. ostreatus on the nematode C. elegans. We found that prior to penetration inside a worm a fungal toxin paralyzed and immobilized, but did not kill C. elegans. This finding opens the possibility for the further study of the effect of paralyzing toxins on host organisms. The membrane permeability of paralyzed worms increased dramatically and leakage products initiated the growth of directional hyphae towards the nematodes. The hyphae penetrated into live C. elegans animals either through natural openings or directly by piercing the cuticle. Upon contact with the nematode cuticle, P. ostreatus attached to it, formed appressoria-like structures and infection pegs, piercing the cuticle and penetrating inside the nematode body. The small zones around the penetration loci are of special interest for the evaluation of initial contacts between two organisms and for the study of the C. elegans local defense response against fungal infection.